At present--in addition to other techniques, e.g. bore diaphragm lining--four basically different excavation pit linings are known, namely sheet pile lining, support plank wall lining, slit wall lining and combinations of these linings.
The invention pertains to a combination that uses a slit wall.
In this regard there have been attempts in the production of excavation pit linings to let down sealing walls in a single-phase slit wall lining, into which supporting elements, such as I-beam section supports then were set vertically. In this case, the slit wall material acts as a gap filler. As construction material, a conventional single phase impermeable diaphragm, e.g., in the form of a finished, dry mixture, is used.
After preparation of the slit wall, e.g., down to the bottom of the excavation, and after hardening of the construction material, the excavation pit was excavated, where the slit wall is exposed on one surface, e.g., on the air side. The single-phase material should ensure a sealing of the excavation pit against the penetration of water. The forces resulting from the water pressure and ground pressure are to be absorbed by the supporting elements, e.g., the I-beam section supports and the single-phase material acting as panel wall, as well as possibly by additional strengthening elements or compression anchors or other reinforcing elements.
The application of this known excavation pit lining combination includes the advantage that they are free of vibrations and can be prepared with relatively simple means, and requires few machines, thus saving space. But it turns out that the supporting properties of the single-phase material are not sufficient and the sealing and supporting properties of the single-phase material are lost relatively quickly during the construction phase. Uncontrolled crack formation and/or material chipping occurs until ultimate collapse of one wall, as a rule in a period in which the structure is not yet completed and the excavated pit wall is intended to perform its function unimpaired. For this reason, the known combination method--even though it is superior to all other methods both in cost and in production engineering--has not been used practically.